With the quick development of the related electronic technology, electronic devices such as computers, mobile phones become necessary auxiliary tools in modern people's daily life. Usually, various kinds of electronic devices all include a mother board with chipsets to perform various functions, passive elements such as resistors and capacitances, and sockets for connecting various functional circuit boards. The chipsets, the passive elements and the sockets are connected to each other via compactness and complex circuits.
As shown in FIG. 1, it is a functional block diagram showing a mother board in the prior art. The mother board 7 is mainly composed of a CPU 70, a north bridge chip 72, a south bridge chip 74, a basic input/output system (BIOS) chip 76 and an input/output (I/O) control chip 78. The north bridge chip 72 is responsible for data transmission and control among the CPU 70, a main memory 710 and a display device (not shown). The south bridge chip 74 is used to enable the CPU 70 to communicate with the BIOS chip 76 and part of peripheral devices. The peripheral devices include an interface expansion area 730, a storage device 732, a network control element 734 and other devices which need high transmission speed. In addition, a serial port 750, a parallel port 752, a keyboard 754, a mouse 756, a power supply 758 and other peripheral devices which only need low transmission speed are controlled by the I/O control chip 78.
Furthermore, the BIOS chip 76 may initialize the chipsets and the peripheral devices on the mother board 7, and it may load the operation system from the storage device 732 to the main memory 710. In addition, the BIOS chip 76 also may allow a user to set particular mechanisms such as a wake on local area network (WOL) mechanism, a wake on keyboard mechanism and a wake on mouse mechanism.
To take the WOL as an example, when the electronic device is shut down normally, an operation system calls the BIOS chip 76 to start the WOL mechanism before the power is cut off. Then, the states of the network control element 734, the south bridge chip 74 and other related units are set to be capable of accepting the WOL by the BIOS chip 76. Afterwards, the operation system controls the power supply 758 to cut off the power. Thus, a user may transmit the waking signal packet (such as the magic packet provided by the AMD Corporation) via a remote server to the network control element 734. The network control element 734 then transmits a waking signal to the south bridge chip 74, and the south bridge chip 74 controls the electronic device to boot according to the waking signal.
In addition, the electronic device usually includes a power switch 80, which is connected to the I/O control chip 78. The power switch 80 may transmit a power control signal to the I/O control chip 78. When the power switch 80 is in normal condition, the power control signal has the first signal level. When the power switch 80 is pressed by the user, the signal level of the power control signal is changed to be the second signal level (usually, the second signal level is lower than the first signal level). When the I/O control chip 78 detects that the signal level of the power control signal is changed, it informs the operation system to perform the above mentioned shutdown process.
However, if the electronic device is not shut down normally, if the user continues pressing the power switch 80 for several seconds to make the electronic device shut down forcibly, the power supply 758 directly cuts off the power which makes the BIOS chip 76 have no enough time to set the network control element 734, the south bridge chip 74 and other related units. Thus, the WOL mechanism loses effectiveness. Similarly, other mechanisms which need to be set before the electronic device is shut down by the BIOS chip 76 may lose effectiveness because of the abnormal shutdown of the electronic device.